Percussive tool.



A. H. GIBSON.

PERCUSSIVE TOOL.

APPLICATION FILED MAYiQ. 1911.

Patented May 4, 1915.

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ARTHUR H. GIBSON, EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RAND COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PERCUSSIVE TOOL.

Specification of Letters Patent.

Patented May 4, 1915.

Application filed May 19, 1911. Serial No. 628,206.

To all whom it may concern:

Be it known that I, ARTHUR H. GIBSON, a subject of the Crown of Great Britain, and resident of Easton, in the county of North ampton and State of Pennsylvania, have invented a new and useful Improvement in Percussive Tools, of which the following is a specification.

This invention relates to percussive tools of that class in which the hammer piston is driven from a pulsator by reciprocating columns of'air and is more particularly directed to a hand hammer drill.

A practical embodiment of the invention is represented in the accompanying drawings in which,

Figure 1 represents the drill in side elevation and the pulsator for driving it, partly in side elevation and partly in section. Fig. 2 is a longitudinal central section through the drill, showing the parts in the position which they assume when the drill steel has been forced up into position to be struck by the piston hammer extension, by weight exerted on the tool. Fig. 3 is a longitudinal central section taken in the opposite direction to Fig. 2, the piston hammer being removed and the drill steel being shown in its normal extended position, and Fig. 4 is a cross section taken in the plane of the line AA of Fig. 1.

The pulsator is denoted by 1, and may be driven from any suitable source, such, for instance, as an electric motor 2. The hammer drill cylinder is denoted by 3 and its hammer piston chamber by 4, within which the piston hammer 5 is fitted to reciprocate. The back head of the hammer cylinder is denoted by 6 and it is provided with suitable handles 7 for manipulating the hammer. The front head of the cylinder 3 is denoted by 8 and it is provided with a chambered extension 9 in the inner end of which the pistonhammer extension 10 is fitted to reciprocate and in the outer end of which the drill steel 11 is fitted to reciprocate. Tie rods 12 serve to hold the, front and back heads and cylinder in assembled adjustment. The chamber 13 in which the piston ham mer extension 10 reciprocates, terminates at the inner end of the socket 14: in which the drill steel 11 reciprocates, with a shoulder 15, so that the walls of the chamber 13 are spaced from the sides of the, drill steel 11 when the inner end of the drill, steelis chamber 1, through a passage 17 provided for, in the present instance, by a pipe 18, which pipe is provided with a manually operated valve 19 for regulating the passage of air through the pipe 18. The passage 17 opens into the hammer piston chamber at at a point intermediate the ends of the cylinder where the said passage will be alternately opened to both sides of the piston hammer 5.

Hose pipe connections 20, 21, lead from the pulsator to the tool cylinder 3. The port 22 for the pipe 20 and the port 23 for the pipe 21 open into the hammer piston chamber 4% at points spaced from the back end and front end of said chamber 4, thus providing air cushions for the hammer piston 5, as it approaches the limits of its rearward and forward movements.

The hollow drill steel 11 is held normally extended with its inner end out of position to be engaged with the piston hammer ex tension 10. In the present instance, this is provided for by providing the drill steel with a collar 24 clamped thereto at a distance from the front end of the extension 9, and interposing a spring 25 between said collar and end of the extension 9. The relation of the parts is preferably such that the inner end of the drill steel, when in its normal position, will occupy a position about flush with the inner end of its socket 1 1, and the tension of the spring 25 may be such that a considerable weight will have to be exerted upon the drill to force the inner end of the steel up into the chamber 13 into position to be struck by the piston hammer extension 10. The drill steel may be turned with the hammer during its operation, as, for instance, by making the drill steel angular in cross section and making its socket to correspond therewith. To prevent leakage of air around the steel at the front end of the piston hammer exten- I the heavy spring 25.

The usual pump 27, such for instance, like that illustrated and described in United States patent to Robert Temple, No. 787,962,

' port 28,

dated April 25, 1905, is provided on the pulsator for raising the air pressure to a predetermined point and maintaining it at such pressure and for restoring the pressure when it is permitted to escape through the passage 17 and hollow drill steel 11.

In operation, as the hammer drill is operated, the dust may be blown out of the hole by the air connection with the interior of the steel from the interior of the hammer iston chamber, which connection is controlled by the valve 19 in the pipe 18. Fur thermore, when the tool is in operation, and if the piston hammer extension is not. striking the steel, the hammer piston cannot.

strike the front end of the cylinder'because of the cushion of air after it closes the Another feature of this tool is that the drill may be caused to strike'light or heavy blows or no blows at all, by simply varying the weight of the operator on thetool.

While I have described this invention in connection with a hammer drill, it is to be understood that it may be used in connection with fluid pressure operated percussive tools Copies of this patent may be obtained for travel with the extension chamber,said pas sage being alternately opened to both sides of the piston as the piston reciprocates.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two witnesses, this twelfth day of May 1911.

ARTHUR H. GIBSON.

Witnesses F. GEORGE BARRY, HENRY C. THEME.

five cents each, by addressing the Commissioner of: Patents Washington, D. C. 

